Intersite Coulomb interaction between Cu 3d and O 2p holes (Upd) is shown to be important in analyzing the optical conductivity and the Cu 2p core-level X-ray photoemission spectrum (XPS) of one-dimensional copper oxides such as Ca2CuO3 and Sr2CuO3 consistently. It is shown that the Cu 2p XPS is rather insensitive to Upd, while the optical gap is expanded by stronger Upd. With Upd around 2 eV, the superexchange coupling constant of Cu 3d spins is also reasonably reproduced. The influence on the Cu 2p XPS of the intersite Coulomb potential of the Cu 2p hole acting on the neighboring O 2p holes is also discussed.